Vehicles with an electric or hybrid drive require electric energy stores, such as for example rechargeable traction batteries, to operate their electric drive unit. At present, these traction batteries are usually embodied as lithium-ion batteries. Such rechargeable batteries of electric vehicles or hybrid vehicles generate heat owing to the high currents which flow during their operation, and this heat has to be discharged. The cooling takes place either by means of a built-in cooling device or by cooling by means of the dynamic wind.
The temperature in passenger compartments of vehicles is dependent on the ambient conditions, for example the external temperature or solar radiation. Therefore, the vehicles are generally provided with a ventilation system with heating and/or cooling devices, for the temperature-controlled ventilation of the passenger compartment.
FR 2 949 096 A3 discloses an electric vehicle having a device for controlling the temperature of a rechargeable traction battery of the vehicle. This device comprises a first flow path which opens into a housing of the electric energy store and has a ventilation system for temperature-controlled ventilation of a passenger compartment of the vehicle, which ventilation system has a heating device and a second flow path which leads from the at least one heating and/or cooling device into the passenger compartment. The device has a supply air inlet for air from the surroundings of the vehicle, which supply air inlet is configured to divide a supply airflow into a first partial flow and a second partial flow, wherein the first partial flow is fed to the first flow path and the second partial flow to the passenger compartment. The first flow path opens into a housing of the traction battery. During ongoing operation, the battery heats up and therefore forms a heating device of the ventilation system of a passenger compartment. The second flow path leads from the battery functioning as a heating device of the ventilation system into the passenger compartment of the electric vehicle. In this context, the battery is cooled and the passenger compartment is heated. In the case of cold temperature, the battery in the quiescent state assumes the low external temperature, which can lead to a power drop of the battery. The temperature control of the electric energy store is therefore possible only to a limited extent by means of this device.
The device, the vehicle and the method according to the disclosure provide the advantage that both electric energy store and the passenger compartment can be temperature-controlled satisfactorily without components of the waste air of the electric energy store which are damaging to passengers in order to enter the passenger compartment.
In the device according to the disclosure there is provision that the two flow paths are connected in the device in such a way that an airflow in each case one of the two flow paths is fluidically independent of an airflow in the respective other of the two flow paths, wherein the device has a heat exchanger, connected in both flow paths, for pure heat exchange between the airflows in the two flow paths. However, this heat exchanger does not permit mixing of these airflows. As a result of the purely thermal connection of the first flow path to the ventilation system of the device, the heating and/or cooling device thereof can also be used to heat and/or cool the electric energy store without components of the waste air of the electric energy store which are damaging to passengers being able to enter the passenger compartment.
The device for controlling the temperature of the electric energy store uses the ventilation system present in many vehicles to perform temperature-controlled ventilation of the passenger compartment of the vehicle. It is therefore, to be precise, a device for controlling the temperature of the electric energy store and for temperature-controlled ventilation of the passenger compartment of the vehicle.
According to one advantageous development of the disclosure, the device also has an air inlet for air from the surroundings of the vehicle. The air inlet is configured to divide an inflow into a first partial flow and a second partial flow, and the first partial flow is fed to the first flow path, and the second partial flow is fed to an inlet of the ventilation system. The air flows are therefore already separated from one another completely when they enter the vehicle.
Generally, the ventilation system can, of course, have any type of heating and/or cooling device such as, for example, a cooling machine, an electric heater, a Peltier element etc. There is advantageously provision that the heating and/or cooling device has a cooling compressor and/or a stationary mode heater.
According to an advantageous embodiment of the disclosure, the device for controlling the temperature of the electric energy store has a first temperature regulating device which itself has a temperature sensor for determining the temperature of the electric energy store and an actuator element for changing the throughflow of the airflow in the first flow path. The sensor is preferably arranged directly on the electric energy store or at least in the corresponding housing.
According to yet another advantageous embodiment of the disclosure, the ventilation system has a second temperature regulating device which itself has a temperature sensor for determining the temperature in the passenger compartment and an actuator element for changing the throughflow of the airflow in the second flow path. The sensor is preferably arranged in the passenger compartment.
Finally, there is advantageously provision that the device has a first air discharge duct for discharging air from the housing of the energy store, and that the ventilation system has a second air discharge duct for discharging air from the passenger compartment, through which air discharge ducts the respective waste air can be discharged into the surroundings of the vehicle. In this context, the ventilation system has, in particular, a return duct, connecting the second air discharge duct to the inlet of the ventilation system, for an air circulation mode of the ventilation system.
The vehicle according to the disclosure has a passenger compartment, an electric energy store and a device for controlling the temperature of the electric energy store, which device comprises itself the following components: (i) a first flow path which leads to the electric energy store and (ii) a ventilation system for temperature-controlled ventilation of a passenger compartment of the vehicle, which ventilation system has a second flow path which leads to the passenger compartment. There is provision here that the device is embodied as a device as specified above. The vehicle is, in particular, an electric vehicle or hybrid vehicle. The electric energy store serves to supply electrical energy to an electric drive of this vehicle and is embodied, in particular, as a rechargeable traction battery.
In the method according to the disclosure for controlling the temperature of the electric energy store of a vehicle by means of a ventilation system for temperature-controlled ventilation of a passenger compartment of the vehicle, a temperature-controlled airflow is fed to the electric energy store by a first flow path, wherein the ventilation system feeds an airflow to the passenger compartment via a second flow path. There is provision that both flow paths lead through a heat exchanger, wherein the airflow which is fed to the energy store is temperature-controlled in the heat exchanger by a transfer of heat between the airflows.
Additional cooling devices for the electric energy store are eliminated by virtue of the purely thermal connection of the first flow path to the ventilation system for temperature-controlled ventilation of a passenger compartment.
When it is low temperatures, the electric energy store is heated, and therefore no reductions in capacity occur. At high temperatures, it is cooled, thereby avoiding overheating of the electric energy store.
According to one advantageous development of the disclosure there is provision that a supply airflow of air from the surroundings of the vehicle is divided in a supply air inlet into a first partial flow and a second partial flow, wherein the first partial flow is fed to the first flow path and the second partial flow to the ventilation system.